The present invention relates to a fuze for an explosive projectile, particularly a submunition projectile (bomblet).
More particularly the present invention relates to a fuze for an explosive projectile, particularly a submunition projectile (bomblet), which is of the type including a first primary firing pin mounted in a housing for axial displacement in the longitudinal direction, a detonation charge carried by a slide disposed in the housing adjacent the primary firing pin, with the slide being mounted for displacement transverse to the longitudinal direction of the housing (and to its center longitudinal axis) between a safety position, wherein the detonation charge is not aligned with the firing pin, and an armed position, wherein the detonation charge is aligned with the firing pin, and a self destruct arrangement provided in the slide, and including an ignition element disposed adjacent an edge of the slide, for causing self destruction of at least the fuze after a given time delay following ignition of the ignition element by a second firing pin, which is mounted in the fuze housing, upon displacement of the slide into the armed position.
Such a bomblet fuze including an axially unscrewable primary firing pin and a slide that is displaceable transversely to the longitudinal direction of the projectile and fuze housing from a safety position into a armed position is disclosed, for example, in EP 0,284,923.A2, corresponding to U.S. Pat. No. 4,811,664. The slide includes an ignition element for a pyrotechnic delay path that is ignited by a second firing pin for self-destruction of the projectile if the detonator has not been actuated by the primary firing pin upon impact on the target. This may happen, for example, if such a secondary projectile (bomblet) ejected from a carrier projectile lands in soft ground, in a swamp, in snow, in tree branches or in a camouflage net.
One drawback in this prior art bomblet construction is the fact that the slide, when the ignition device is in the armed position, projects far and unprotected from the side of the fuze housing. In rainy weather, for example, this may easily produce malfunctions in the firing of the detonation charge or in the firing of the exposed ignition element for the delay charge for self-destruction.
Another drawback of this known arrangement is the arrangement of the second firing pin for igniting the ignition element at the outer, unprotected end of the slide itself which projects far from the side of the fuze housing. This second firing pin is provided with a heavy percussion member and is rotatably fastened to the slide by means of a pin. In the armed position attained by transverse displacement of the slide partially out of the fuze housing, the percussion member is to become effective due to centrifugal forces generated from the inherent rotation of the bomblet and the solid firing pin is to perform a movement of about 90.degree. on a small-radius partial circle so as to enter into the ignition element. The firing pin tip has the shape of a solid cone which is flattened on one side, possibly in order to facilitate entry into the ignition element over a small circular arc. This fuze construction has the further great drawback that the slide which projects far from the fuze housing and the heavy firing pin-percussion member assembly on its exterior create eccentricities during rotation and thus cause destabilizing forces to act on the bomblet.
Federal Republic of Germany DE-OS 3,333,312, corresponding to U.S. Pat. No. 4,612,858, discloses a further bomblet fuze with a self-destruct capability. In this arrangement, a solid, conical second firing pin is fastened to the interior housing wall in order to activate the ignition composition and the delay composition for self-destruction of the bomblet. The drawback of this prior art bomblet fuze is the solid, conical firing pin and the spatial arrangement of the delay composition in the fuze housing between the slide and primary explosive charge. This increases the structural height of the fuze and the ignition composition is not connected in one piece with the delay path so that the ignition must occur "around the corner" so to speak.
Moreover, each ignition element for the delayed charge is provided with an injection opening that is covered by a foil and is entered by the injection pin, that is the firing pin, to initiate the charge. The prior art second firing pin in solid, conical form more or less closes this opening during the ignition process, depending on how deep the pin penetrates. For secure ignition, the firing pin should penetrate as deeply as possible, but then the injection opening is closed completely and the poor provisions for dissipation of the developing combustion gases may cause the ignition to die out.